>Are there any rules prescribing (say) that a tour de France bike must use a normal (double triangle) design? Yes. The UCI is the international governing body

>Are there any rules prescribing (say) that a tour de France bike must use a normal (double triangle) design? Yes. The UCI is the international governing body for most forms of cycle sport. UCI regulation 1.3.020 states: For road, track and for cyclo-cross competitions, the frame of the bicycle shall be of a traditional pattern, i.e. built around a main triangle. A complex set of rules govern the permissible shape and construction of a bicycle used in UCI-sanctioned competition, similar to the rules governing Formula 1 or NASCAR. These rules are shaped by competing and often contrary aims of many stakeholders - to ensure safety, to maintain the traditional aesthetics of cycling, to allow fair competition for less well-funded nations and teams, to allow equipment manufacturers to showcase innovative new products etc. The design of a modern racing bicycle is guided as much by politics as engineering. https://assets.ctfassets.net/761l7gh5x5an/wQympSG6EWlKq6o6HKw9E/06476118f9497fcaaec76bf422475a80/1-GEN-20240101-E.pdf https://assets.ctfassets.net/761l7gh5x5an/wQympSG6EWlKq6o6HK... https://assets.ctfassets.net/761l7gh5x5an/7s1ma6mVAVlFwi8rRgy0Iw/50fda3854ab916cc8a7ff346233c2df9/Clarification_Guide_of_the_UCI_Technical_Regulation_-_20240110_-_ENG.pdf https://assets.ctfassets.net/761l7gh5x5an/7s1ma6mVAVlFwi8rRg...